1. Technical Field
The present invention relates to a laser navigation module.
2. Description of the Related Art
Generally, a personal mobile communication terminal such as a cellular phone, a smart phone, or the like includes a user interface using a keypad, which includes input buttons for a number, a character, and a direction.
Recently, as a wireless internet service such as a wireless broadband (WIBRO) service has been commercialized, a Windows operating system supporting a graphic user interface (GUI) has also been used in the personal mobile communication terminal.
As the operating system supporting the GUI has been used as a user interface of the personal mobile communication terminal as described above and the demand for development of an input device capable of being conveniently and simply used by users has been urgently increased, apparatuses such as a touch key, a joystick, an optical pointing device, and the like, performing sequential input on a keypad displayed on a display screen of the mobile communication terminal have been developed. One of the apparatuses is a laser navigation module including a window and a lid.
The laser navigation module has a problem in that it does not include a separate lighting device, such that it is difficult for users to use the laser navigation module in a dark location.
More specifically, FIG. 1 is an exploded perspective view schematically showing a laser navigation module, which is an input device for a mobile communication terminal, according to the prior art. As shown in FIG. 1, the laser navigation module 100 is configured to include a window 110, a housing 120, a lid 130, a control integrated circuit (IC) chip 140, a printed circuit board 150, and a dome switch 160.
The window 110 transmits laser beam radiated from a light source therethrough, and blocks inflow of a visible ray. In addition, the window is received in the housing 120.
The lid 130, which is disposed under the window 110, serves as a shielding part for blocking inflow of spill light and includes a circular hole 131 and a rectangular through hole 132. The circular hole 131 is to transmit the laser beam radiated from the light source therethrough, and the rectangular through hole 132 is to transmit laser beam collected by being reflected and refracted on a body, or the like, of a user in contact with the window therethrough.
The control IC chip 140 includes a VCSEL 141, which is a light source of the laser beam, is to calculate a displacement value between the laser beams collected by being reflected and refracted from the window, and is coupled to the printed circuit board 150. The dome switch 160 is coupled to a lower portion of the printed circuit board 150. The dome switch 160 is to sense pressing of the user to transfer a selection signal of the user to a controller (not shown) disposed on a lower portion thereof.
As described above, the laser navigation module according to the prior art does not include a separate lighting device, such that it is inconvenient for users to use the laser navigation module in a dark location, and may have the lighting device mounted in an outer portion of the laser navigation module; however, it is very difficult to mount the lighting device in an inner portion of the housing of the laser navigation module manufactured at a very small size. In addition, the laser navigation module according to the prior art has a technical difficulty in designing such that the lighting device is mounted without interfering with a light path of the VCSEL, which is a light source, and has a problem in which it may not uniformly radiate the light radiated from the lighting device in the inner portion of the housing.